title: Fiber-based cryogenic and time-resolved spectroscopy of PbS quantum dots.
abstract: PbS quantum dots are promising active emitters for use with high-quality Si nanophotonic devices in the telecommunications-band. Measurements of low quantum dot densities are limited both because of low fluorescence levels and the challenges of single photon detection at these wavelengths. Here, we report on methods using a fiber taper waveguide to efficiently extract PbS quantum dot photoluminescence. Temperature dependent ensemble measurements reveal an increase in emitted photons concomitant with an increase in excited-state lifetime from 58.9 ns at 293 K to 657 ns at 40 K. Measurements are also performed on quantum dots on high-Q (>10(5)) microdisks using cavity-resonant, pulsed excitation.
authors.affiliation: Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6203, USA. matthew.rakher@gmail.com
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Rakher
authors.forename: Ranojoy
authors.initials: R
authors.lastname: Bose
authors.forename: Chee Wei
authors.initials: CW
authors.lastname: Wong
authors.forename: Kartik
authors.initials: K
authors.lastname: Srinivasan
mesh_terms: D003080:Cold Temperature; D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000295:instrumentation* / Q000379:methods*; D007854:Lead / Q000737:chemistry*; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000295:instrumentation*
chemical_list: D018036:Selenium Compounds; C088065:lead selenide; D007854:Lead